Conventional image-forming devices, such as laser printers, have been provided with a main device body in which a process cartridge can be detachably mounted to facilitate replacement of a photosensitive drum, toner, and the like.
The process cartridge is configured of a photosensitive member cartridge, including a photosensitive drum, and a toner cartridge that accommodates toner. The photosensitive member cartridge and toner cartridge are removed together from the main device body as the process cartridge, after which the two cartridges can be separated and replaced individually.
Generally, the photosensitive member cartridge is provided with a charger for charging the surface of the photosensitive drum. Often, a Scorotron charger is used for charging the photosensitive drum by applying a high voltage to a charging wire stretched tightly in the axial direction of the photosensitive drum to produce a corona discharge. In this type of image-forming device using a Scorotron charger, silica and other substances in the toner become deposited on the surface of the charging wire after image forming operations are repeatedly performed. A buildup of deposited matter on the charging wire can degrade the charging performance of the wire, causing problems in printing. Japanese patent application publication No. HEI-10-301368 discloses a cleaning member, which is often disposed in the photosensitive member cartridge so as to be moved along the charging wire. By operating the cleaning member, the user can remove matter deposited on the charging wire.